1. Field
Example embodiments relate to a semiconductor memory device, and more particularly to a refresh counter in a semiconductor memory device, and method of performing a refresh for the semiconductor memory device.
2. Discussion of the Related Art
Along with rapid developments in capacities and speeds of semiconductor memory devices widely used in electronic devices, power consumption of semiconductor memory devices has been increasing. Particularly, in case of portable electronic devices, it is very important to reduce power consumption of semiconductor memory devices in portable electronic devices.
For example, a dynamic random access memory (DRAM) is a volatile semiconductor memory device which stores data by using charges stored in a capacitor. Since charges stored in a capacitor may be leaked in various ways as time passes, a DRAM has a finite data retention characteristic. For solving finite data retention, it is typically necessary for a DRAM to refresh periodically to charge/discharge a capacitor according to data stored in the DRAM.
In general, if a refresh period becomes shorter or multiple word lines are simultaneously selected, data retention characteristic may be improved but power consumption may be increased during refreshing a DRAM.